You're making me eyeroll somewhat CurlyWurlyTwirly. As long as the frequent posters keep the royal S&B chat going, these small side conversations will naturally peter out without the need to be rude about it.
Regarding the Royal premises, Sophie and Edward do pay for the lease of Bagshot. I read it was £90,000 per year, so not an insignificant amount.
Whilst they do own an obscene amount of property, it makes me feel a teeny bit better about it that at least they do have to pay a proper rent on the lease.